WASHINGTON — All Amtrak trains in the Northeast Corridor will have a system in place to automatically regulate their speed by the end of the year, the railroad's president told a House committee Tuesday.

Amtrak President Joseph Boardman told the House Transportation and Infrastructure Committee that the railroad would meet the Dec. 31 deadline for installing positive speed control system along the entire Northeast Corridor from Washington to Boston, as required by federal law.

"I promise you that by the end of the year, this system, which will dramatically enhance safety, will be complete and in operation," Boardman said.

Sarah Feinberg, scting administrator of the Federal Railroad Administration, called positive train control "the single most important railroad safety technological development in more than a century."

The National Transportation Safety Board in January called for the installation of a speed control system that would have prevented the May 12 fatal derailment of an Amtrak train in Philadelphia that killed eight people and injured more than 200. Amtrak estimated the cost of the accident at $8.7 million, the NTSB said.

Hart said that the NTSB investigation found that the engineer made phone calls, sent texts and used data on his cell phone on the day of the accident, but it is still unknown whether this activity occurred while he was operating the train.

In addition, while the NTSB found windshield damage, investigators still don't know if it is from the crash itself or from objects being thrown at passing trains at the time of the derailment. The NTSB said it was investigating reports of vandals throwing rocks or other objects at passing trains around the time of the derailment. The engineer of a commuter line reported that the windshield of his locomotive had been shattered, Hart said, citing dispatch tapes. An investigation assisted by the Federal Bureau of Investigation found no evidence that someone had shot at the train.